Last year, Walsh and two others, Rafael Rivera and Long Zheng, created the ChevronWP7 unlocking tool for Windows Phone 7, but yanked the tool after reaching an agreement with Microsoft. In December 2010, Microsoft promised to talk with them about officially supporting applications not available through the company's approved-software marketplace.

Microsoft later met with the trio at its Redmond, Wash. headquarters.

In a blog published Monday, Walsh explained how to use his ChevronWP7.Updater and warned users they were on their own if they tried it.

"Disclaimer, use this at your own risk, if this voids your warranty I'm not being held responsible, blah blah all that junk," said Walsh. " There is NO revert process [so] again, flash at your own risk."

The update tool applies all Windows Phone 7 updates that Microsoft has created to this point, including the "NoDo" update that adds copy and paste functionality, and the February update designed to prepare smartphones for NoDo.

Updates for Windows Phone 7 have been plagued with problems. Users have bashed Microsoft over a sluggish roll-out, and experts have criticized the company for not anticipating that the delays would infuriate early adopters and loyal fans.

Walsh's tool lets users sidestep the carriers and retrieve the official updates directly from Microsoft.

"I didn't hack the device, I used the official update functionality," Walsh wrote on Twitter. "I just went around the typical carrier bulls***."

To use ChevronWP7.Updater, users must first download Microsoft's Windows Phone Support Tool, an application designed to fix problems with the operating system's update mechanism.

The Windows Phone Support Tool can be downloaded from Microsoft's site using links found in this support document.

Microsoft did not immediately reply to a question about whether others could access the Windows Phone 7 updates to build tools that, while posing as an updater, might also include malware. Walsh promised to release the source code for his tool on Tuesday, a move that would likely show others how to grab Windows Phone 7 updates using Microsoft's own technology.

Microsoft has traditionally taken a dim view of updates that don't come directly from the company or its sanctioned services.

It did the same today.

"We encourage people to use the Windows Phone Support Tool as supplied by Microsoft to ensure the best possible user experience," a company spokesman said. "We're aware of Mr. Walsh's work and have been in contact with him regarding his intent and any potential implications."